Reaction products of polyamines and polybasic acid esters as antiscuff additives



May 23, 1967 M. J. FUREY ETAL 3,321,404

REACTION PRODUCTS OF POLYAMINES AND POLYBASIC ACID ESTERS AS ANTISCUFF ADDITIVES Filed 001:. 1, 1965 REACTION PRODUCTS F POLYAMINES AND POLYBASIC ACID ESTERS AS ANTISCUFFING AGENTS 3 5 RATING I 2365 ppi 30 PURE XYLENE RATING I. 522 ppi SCUFF 0 l I l I l l 0 5 l0 I5 20 3O 4O APPLIED LOAD (POUNDS) Michael J. Furey Harv J Schugur Inventors 1 Patent Attorney United States Patent 3,321,404 REACTION PRODUCTS OF POLYAMINES AND POLYBASIC ACID ESTERS AS ANTISCUFF ADDITIVES Michael J. Furey, Latham, and Harvey J. Schugar, New

York, N.Y., assignors to Esso Research and Engineering Company, a corporation of Delaware Filed Oct. 1, 1965, Ser. No. 495,024 8 Claims. (Cl. 252-515) The present invention is a continuation-in-part of Ser. No. 354,993, filed Mar. 26, 1964, now abandoned.

The present invention is broadly concerned with a novel class of lubricity additives, additive concentrates, and oleophilic liquid compositions containing these additives. The invention is more specifically concerned with improving the lubricity of hydrocarbon liquids such as gasolines, aviation turbo fuel, kerosene, diesel fuel, lubricating oil and mineral lubricating oils. Other base fluids include liquid carbohydrates and esters such as dioctyl sebacate and didecyl adipate. The present invention also contemplates the use of the lubricity additives in solid products such as paraflin wax, lubricating grease and Carbowax. The invention in one specific aspect relates to improving the lubricity of middle distillates, particularly jet fuels. The additives of the present invention comprise a reaction product between a polyaminepreferably an oil insoluble polyamine-and a dialkyl ester of a dicarboxylic acid.

The lubricity additives of the present invention are preferably made from amine compounds selected from the class of polyamines and esters of dicarboxylic acids that are obtained by the polymerization of dienoic or trienoic monocarboxylic acids, Thus, the invention is concerned with a novel class of lubricity additives which are specifically adapted for use in conjunction with oleophilic liquids such as hydrocarbon lubricants and jet fuels. In accordance with a specific adaptation of the present invention, middle distillate compositions such as iet fuels are improved with respect to their lubricity by incorporating therein an effective amount of a reaction product of a polyamine, preferably an oil insoluble polyamine with a dialkyl ester of a dicarboxylic acid. Very desirable esters include the dimethyl ester of dilinoleic acid, the dimethyl ester of dioleic acid and the dimethyl ester of the mixed dimer of linoleic and oleic acids.

Many oil compositions are designed for lubricating under boundary conditions (e.g. crankcase oils, aviation oils and gear oils) where wear of the metal surfaces under heavy loading is a serious problem. One common example of such heavy loading occurs in the operation of the valve lifter mechanism of gasoline engines.

Here pressures of 50,000 to 100,000 psi. can occur between the valve lifter and its actuating cam, and metal wear is accordingly high. It has now been found that metal wear can be significantly reduced by adding to an oleophilic liquid such as a mineral oil lubricant, a reaction product of a polyamine, preferably an oil insoluble polyamine with a dialkyl ester of a dicarboxylic acid. It is preferred that the dicarboxylic acid be characterized by having at least 9 carbon atoms, preferably 12 to 42 carbon atoms, between the respective carboxylic groups. A particularly desirable reaction product is that formed between a diester of a dimer acid, such as linoleic dimer, oleic dimer or the mixed dimer of linoleic and 3,321,404 Patented May 23, 1967 oleic acids and tetraethylene pent-amine. Other esters, as for example dimethyl sebacate, dimethyl malonate, dibutyl malonate and dimethyl phthalate are satisfactory.

Other additives, of course, may be added to the oil compositions of the present invention to form a finished oil. Such additives include oxidation inhibitors such as phenothiazine or phenyl a-naphthylamine; rust inhibitors such as lecithin or petroleum sulfon'ates; sorbitan monooleate; detergents such as the barium salt of isononyl phenol sulfide; pour point depressants such as copolymers of vinyl acetate with fumaric acid esters of coconut oil alcohol-s; viscosity index improvers such as polymethacrylates; etc.

As pointed out heretofore, the preferred dicarboxylic acids utilized are those which contain at least 9 carbon atoms between the respective groups. It is greatly preferred that the number of carbon atoms between the carboxylic groups be in the range from about 12 to 42. Specific examples of these acids are the dimers of linoleic acid, oleic acid, the mixed dimer of linoleic and oleic acids and the dime-r of dodecadienoic acid. It is also possible to employ the dimer of dicyclopentadiene dioic acid. While the foregoing acids are preferred, similar dicarboxylic acids such as VR-l described in US. 2,833,713 and D-50 described in US. 2,470,849 may be used. The dienoic or trienoic monocarboxylic acid, that is polymerized to give the dicarboxylic polymer, can have from 12 to 30 carbon atoms. Extremely suitable dimer acids for use in the present invention are commercially available from Emery Industries Inc. under the trade name of Empol dimer acids. These dimer :acids are available in various grades of dimer acid purity relative to trimer and monobasic acid content. For example, Empol 1014 dimer acid consists of dimer acid, a trace of monobasic acids and the remainder essentially consists of trimer acid. Also available are Empol 1018 dimer acid (containing 17% trimer and a trace of monobasic acid), Empol 1022 dimer acid (19 to 22% trimer and 2 to 5% monobasic acids) and Empol 1024 dimer acid (containing the same trimer acid content as Empol 1022 but containing only a trace amount of monobasic acid). The specifications and typical compositions of the Empol dimer acids discussed above are given in Table I.

1 Maximum.

The commercial dimer acids discussed above are generally produced by polymerization of unsaturated C fatty acids to form C dibasic dimer acids. Depending on the raw materials used in the commercial process, the C monomeric acid may be linoleic acid or oleic acid or mixtures thereof. The resulting dimer acids may therefore be the dimers of linoleic acid, oleic acid or a mixed dimer of linoleic and oleic acid. Representative formulas of the foregoing monomeric and dimer acids may be illustrated as follows (it should be noted that the structure generally given for linoleic acid is that of 9,12-octadecadienoic acid but it is believed that prior to dimerization this acid isomerizes to the 9,11 structure, see in this regard the article Dimer Acids, the Journal of the American Oil Chemists Society, vol. 39, December 1962, p. 535, J. C. Cowan):

300 C. 9, 12 linoleic acid 2 molecules 9,11 acid 9,11lino1eie acid HO O C (CH2)7CH=CIIH (OHzlsCHs HOOC(CH2)7 (CH2)5CH3 Linoleic acid dimer (dilinoleic acid) 2 molecules oleic acid CH3(CH2)7CH=CH(CHz) COOH Diels-Alder A CH3(CH2)7CH2OH(CH2)7G O OH Oleie acid dimer (dioleic acid) Diels-Alder 9,11 Linoleic Acid Oleic Acid CH3(CH2)4CHCH=CH CH=OH(CH;)1C O OH Mixed dimer It should be noted that the above structural formula only indicate one of the several possible structural isomers. It is believed that the commercial dimer acids would contain mixtures of such structural isomers.

The dimer acid of linoleic acid with which one embodiment of the present invention is concerned is a C dimer acid and is described in U.S. Patent 2,424,588, issued July 29, 1947, and entitled Lubricant Composition; inventors: W. J. Sparks et a1. It is to be understood as indicated in the specifications for the commercial dimer acid that the dimer acid utilized in the practice of the present invention is not necessarily 100% dimer acid.

For example, the following compositions of acid were reacted with ethylene glycol wherein compositions A, B and C produced a satisfactory product and composition D produced a reaction product which was not soluble. Composition A exhibited the highest solubility in hydrocarbons, The content of each of the foregoing compositions is shown in Table II.

TABLE II Composition, Wt. Percent Thus, it is essential that the amount of dimer acid present in the acid composition be at least 50% and pref- 4 erably above such as by weight. It is to be understood that, under certain circumstances, these dicarboxylic acids can be substituted acids such as with bromine, fluorine or a 'hydroxy group.

Thus, in essence, the present invention uses a reaction product between a dialkyl ester of a dicarboxylic acid and a polyamine, preferably an oil insoluble polyamine. A very desirable reaction product is a reaction product between di-Z-ethyl-hexyl-sebacate and triethylene tetramine.

Specific examples of the foregoing dicarboxylic acids are: dimer acids (e.g. dilinoleic acid and dioleic acid); straight chain aliphatic dibasic acids, such as malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and dodecadienoic acid; benzene polycarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, hemimellitic acid, trimellitic acid, trimesic acid, prehnitic acid, mellophanic acid, pyromellitic acid, benzene pentacarboxylic acid and mellitic acid; and others such as diphenic acid, diglycolic acid and d-tartaric acid.

Examples of alcohols which may be used to esterify these polybasic acids are methanol, ethanol, propanol, isopropanol, butanol, isobutanol and pentanol. Other alcohols are benzyl alcohol, cyclohexanol and 2-ethyl hexanol. These esters may also be mixed esters such as monoethyl monopropyl ester of the dimer of a dicarboxylic acid such as the dimer of linoleic acid.

The polyamine is a compound containing two or more amine groups. Some broad examples of polyamines are diamines, triamines, tetramines, and pentamines. Specific examples are dimer diamines made from dilinoleic acid, or dioleic acid, tetraethyilene pentamine, propylene diamine, irnino-bis-propyl amine, hexamethylene tetramine, 1,4-bis (aminomethyl)-cyclohexane, 1,8-p-menthane diamine and fatty acid 1,3 propylene diamine compounds. It is also possible to use hydroxy amine compounds since these are also difunctional.

The polyamines may contain aliphatic, alicyclic or aromatic groups or mixed groups such as alkyl-aromatic.

While the over-all objective of the present invention is to improve the anti-scufiing and anti-wear properties of fluids, one particular objective of the present invention is to improve the lubricity of distillate fuels boiling in the range from about 50 to 750 F. Thus, in accordance with the present invention, middle distillate compositions are improved with respect to their lubricity by incorporating therein an effective amount of the additive of the present invention.

It is well known in the art to improve the quality of jet fuels by various refining techniques in order to remove from these fuels undesirable constituents such as polar compounds, sulfur compounds, and nitrogen compounds. These compounds are removed in order to improve engine performance and lengthen the hours the engine can be operated without major overhauling, but it has been found that when the viscosity of these fuels is relatively low and wherein certain impurities are removed to below a maximum, the finished pure fuel lacks lubricity, which is essential in order to keep the engine parts from excessive wear and a relatively short life. These engine parts among others comprise the fuel pumps, the gears, the bearings and any other parts wherein scufiing and wear is a problem.

Such fuels include aviation turbo-jet fuels, rocket fuel (MILR-25 5 76B), kerosenes, diesel fuels and heating oils. Aviation turbo-jet fuels in which the polybasic acid esters and polyamines may be used normally boil between about 50 and about 550 F. and are used in both military and civilian aircraft. Such fuels are more fully defined by US. Military Specifications MILF5624F, MIL-F- 25656A, MIL-F-25554A, MILF25558B, and amendments thereto, and in ASTM D-1655-62T. Kerosenes and heating oils will normally have boiling ranges between about 300 and about 750 F. and are more fully described in ASTM Specification D-396-48T and supplements thereto, where they are referred to as No. l and No. 2 fuel oils. Diesel fuels in which the polybasic acid ester/polyamine reaction products may be employed are described in detail in ASTM Specification D-975-35T and later versions of the same specification.

Particularly desirable base fuels wherein the present reaction products are most effective are those base fuels wherein the viscosity is below about 3 centistokes and which fuels are substantially free of polar compounds, sulfur compounds, and nitrogen compounds. In essence, the concentration of these compounds is less than about 0.01% by weight which is secured when the jet fuel is highly refined, such as by hydrofining.

The additives of the present invention may be employed in conjunction with a variety of other additives commonly used in fuels such as those set forth above. Typical of these additives are rust inhibitors, anti-emulsifying agents, corrosion inhibitors, anti-oxidants, dispersants, dyes, dye stabilizers, haze inhibitors, antistatic agents and the like. It will frequently be found convenient to prepare additive concentrates for use in the various types of fuels and thus add all of the additives simultaneously.

Thus, in accordance with the present invention, reaction products of dialkyl esters of a dicarboxylic acid with polyamines comprise new valuable additives for jet fuels. If the additive mixtures of the present invention are used as an additive concentrate, the concentrate may consist essentially of from about 25 to 75% of the additive, the remainder being a satisfactory solvent such as kerosene, a Varsol, a naphtha and the like. The preferred concentrate contains about 50 to 60% of the additive in the solvent.

When the additive is used in conjunction with oleophilic liquid, the concentration may vary appreciably. For example, when the additive mixture is used in a fuel, the concentration is in the range from about 0.001 to 1.0% by weight, preferably in the range from about 0.01 to 0.5% by weight. On the other hand, if the additive is used with a hydrocarbon lubricating oil the concentration may vary in the range from about 0.001 to 4.9% by weight, preferably in the range from about 0.1 to 2.0% by weight. It is preferred that the mole ratios of amine compounds and the dicarboxylic ester be about 1/1 although the ratios may vary from 0.5/1 to 1.5/1.

In order to further illustrate the invention, a number of tests were carried out using the additives of the present invention in base jet fuels and the load carrying capacity of the fuels determined.

Example 1 A reaction product of di-Z-ethyl-hexyl sebacate (DOS) and triethylene tetramine (TET) was prepared as follows:

0.1 mole (16 g.) of TET was added to 0.1 mole of DOS (39.8 g.) and heated without solvent for three hours at 120 C. and two additional hours at 150 C. The reaction was carried out in a 100 m1. flask equipped with a Teflon coated stirring magnet. The reactants were not completely miscible below about 70 C. The singlephase reaction product was darker and more viscous than the reactants and soluble in benzene and toluene.

The infrared spectrum of the reaction product contained both amide and ester carbonyl peaks in approximately equal intensity.

A 0.4% solution of the reaction product in xylene was submitted for a Ryder Gear Scuff Test. The comparison of xylene with and without additive is shown on the attached graph. Pure xylene is a poor lubricant as shown by its low Ryder rating of 520 lbs/inch. The addition of 0.4% of the TET-DOS reaction product caused a striking improvement in anti-scufling action (2365 lbs./ inch). Neither amines nor esters of this type are effective load-carrying additives for hydrocarbons.

Ryder Gear Test (Ryder, E. A., ASTM Bulletin 184, 41 (1952)). The ratings represent the load in pounds/inch of tooth width to produce a. given amount (22%%) of gear scutfing.

One explanation of the scuff plateau on the attached graph for the blend containing the DOS-TET reaction product is that a lubricating film forms on the gear teeth.

Thus the present invention is concerned with the use of reaction products of'polyamines and polybasic acid esters as anti-scufling additives in any medium (e.g. hydrocarbons, synthetic lubricating oil, etc.). The most important requirement is that the resultant product be sufiiciently soluble in the fluid used. The polyamines and polybasic acid esters may contain alkyl, aryl and alicyclic groups or mixed alkyl-aryl etc. groups. Examples of the general types of compounds which maybe used are shown below:

Polyamines H N(CH NH Where 21:0 to 40 H N(CH CH NH), CH CH NH 21:0 to 10 Tallow 1,3 propylene diamines (e.g. Duomeens) Polyamino benzenes Phenylene diamines Dimer diamine Esters of polybasic acids where 11:0 to 40 and R=alkyl, arylate Phthalates Pyromellitates Maleates and fumarates What is claimed is:

1. An oleophilic liquid composition of improved lubricity which comprises a major amount of an oleophilic liquid selected from the group consisting of lubricating oils and normally liquid hydrocarbon fuels and containing dissolved therein from about 0.001 to about 4.9% by weight of an additive which comprises an amido-ester reaction product formed by reacting a hydrocarbon polyamine containing from 3 to 36 carbon atoms with a di- (C C alkyl) ester of a dicarboxylic acid having a bivalent hydrocarbon radical of 1 to 42 carbon atoms between the carboxyl groups.

2. Composition as defined by claim 1 wherein said additive is a reaction product between triethylene tetramine and di-2-ethyl-hexyl sebacate.

3. Composition as defined by claim 1 wherein said oleophilic liquid composition comprises a lubricating oil composition.

4. Composition as defined by claim 1 wherein said oleophilic liquid composition comprises a jet fuel and wherein the amount of additive dissolved therein is in the range from about 0.001 to 1.0% by weight.

5. Composition as defined by claim 4 wherein the concentration of additive dissolved in said jet fuel is in the range from about 0.01 to 0.5% by weight.

6. Composition as defined by claim 1 wherein said oleophilic liquid is a hydrocarbon distillate fuel boiling in the range from about 50750 F.

7. Additive concentrate suitable for the addition to oleophilic liquids which consists essentially of from about 40 to about by weight of an amide-ester reaction product formed by reacting a hydrocarbon polyamine containing from 3 to 36 carbon atoms with a di-(C C alkyl) ester of a 'dicarboxylic acid having a bivalent hydrocarbon radical of 1 to 42 carbon atoms between the carboxyl groups, dissolved in an oleophilic liquid selected from the group consisting of lubricating oils and normally liquid hydrocarbon fuels.

8. Composition as defined by claim 7 wherein said solvent comprises a kerosene.

(References on following page) 7 8 References Cited by the Examiner 3,214,460 10/1965 McGee et a1. 252--51.5 X 3,219,666 11/1965 Norman et a1. 25251.5 X

UNITED STATES PATENTS Peterson 25251.5 X FOREIGN PATENTS Messina 25251.5

Messina 252 51 5 5 651,827 11/1962 Canada.

Smith et a1 44-71 X Thompson 44 71 X DANIEL E. WYMAN, Pllmary Examiner. Halter et 1 44 P. P. GARVIN, Assistant Examiner. 

1. AN OLEOPHILIC LIQUID COMPOSITION OF IMPROVED LUBRICITY WHICH COMPRISES A MAOR AMOUNT OF AN OLEOPHILIC LIQUID SELECTED FROM THE GROUP CONSISTING OF LUBRICATING OILS AND NORMALLY LIQUID HYDROCARBON FUELS AND CONTAINING DISSOLVED THEREIN FROM ABOUT 0.00J TO ABOUT 4.9% BY WEIGHT OF AN ADDITIVE WHICH COMPRISES AN AMIDO-ESTER REACTION PRODUCT FORMED BY REACTING A HYDROCARBON POLYAMINE CONTAINING FROM 3 TO 36 CARBON ATOMS WITH A DI(C1-C8 ALKYL) ESTER OF A DICARBOXYLIC ACID HAVING A BIVALENT HYDROCARBON RADICAL OF 1 TO 42 CARBON ATOMS BETWEEN THE CARBOXYL GROUPS. 